 /*******************************************************************************
  * Copyright (c) 2006, 2007 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/

 package org.eclipse.ui.internal.quickaccess;

 import java.util.Collection ;
 import java.util.HashMap ;
 import java.util.Iterator ;
 import java.util.Map ;

 import org.eclipse.core.commands.Command;
 import org.eclipse.core.commands.ParameterizedCommand;
 import org.eclipse.core.commands.common.NotDefinedException;
 import org.eclipse.core.expressions.IEvaluationContext;
 import org.eclipse.jface.resource.ImageDescriptor;
 import org.eclipse.ui.PlatformUI;
 import org.eclipse.ui.commands.ICommandService;
 import org.eclipse.ui.handlers.IHandlerService;
 import org.eclipse.ui.internal.IWorkbenchGraphicConstants;
 import org.eclipse.ui.internal.WorkbenchImages;
 import org.eclipse.ui.internal.handlers.HandlerService;

 /**
  * @since 3.3
  *
  */
 public class CommandProvider extends QuickAccessProvider {

     private Map idToElement;
     private IEvaluationContext contextSnapshot;
     private HandlerService realHandlerService;
     
     public CommandProvider() {
         // initialize eagerly
 saveApplicationContext();
         getElements();
     }

     public String getId() {
         return "org.eclipse.ui.commands"; //$NON-NLS-1$
 }

     public QuickAccessElement getElementForId(String id) {
         getElements();
         return (CommandElement) idToElement.get(id);
     }

     public QuickAccessElement[] getElements() {
         if (idToElement == null) {
             idToElement = new HashMap ();
             ICommandService commandService = (ICommandService) PlatformUI
                     .getWorkbench().getService(ICommandService.class);
             final Collection commandIds = commandService.getDefinedCommandIds();
             final Iterator commandIdItr = commandIds.iterator();
             while (commandIdItr.hasNext()) {
                 final String currentCommandId = (String ) commandIdItr.next();
                 final Command command = commandService
                         .getCommand(currentCommandId);
                 if (command != null && command.isHandled()
                         && command.isEnabled()) {
                     try {
                         Collection combinations = ParameterizedCommand
                                 .generateCombinations(command);
                         for (Iterator it = combinations.iterator(); it
                                 .hasNext();) {
                             ParameterizedCommand pc = (ParameterizedCommand) it.next();
                             String id = pc.serialize();
                             idToElement.put(id,
                                     new CommandElement(pc, id, this));
                         }
                     } catch (final NotDefinedException e) {
                         // It is safe to just ignore undefined commands.
 }
                 }
             }
         }
         return (QuickAccessElement[]) idToElement.values().toArray(
                 new QuickAccessElement[idToElement.values().size()]);
     }

     public ImageDescriptor getImageDescriptor() {
         return WorkbenchImages
                 .getImageDescriptor(IWorkbenchGraphicConstants.IMG_OBJ_NODE);
     }

     public String getName() {
         return QuickAccessMessages.QuickAccess_Commands;
     }
     
     private void saveApplicationContext() {
         realHandlerService = (HandlerService) PlatformUI.getWorkbench().getService(IHandlerService.class);
         contextSnapshot = realHandlerService.getFullContextSnapshot();
     }
     
     HandlerService getRealHandlerService() {
         return realHandlerService;
     }
     
     IEvaluationContext getContextSnapshot() {
         return contextSnapshot;
     }
 }

